Truss Foundations for Frost-Heave and Other Reactive Soil Environments

This is a continuation of U.S. Patent Application No. U.S. Ser. No. 18/439,091 filed Feb. 12, 2024 which is a continuation-in-part of U.S. patent application Ser. No. 17/187,488 filed on Feb. 26, 2021, now U.S. Pat. No. 12,021,483, titled “Truss foundations for frost-heave environments,” which claims priority to U.S. Provisional Ser. No. 62/982,080 filed on Feb. 27, 2020, titled “Single-axis tracker foundations”, the disclosures of which are hereby incorporated by reference in their entirety.

Single-axis trackers have become the most popular form factor for so-called utility scale solar arrays. These systems consist of rows of solar panels attached to North-South oriented torque tubes that move slowly from an East-facing to West-facing orientation through the course of each day to keep the panels perpendicular to radiation from the sun. These structures are typically supported by rows of ground penetrating foundations. Historically, wide-flange steel beams known as H-piles were used to support single-axis trackers. However, more recently, the Applicant of this disclosure has introduced an A-frame-shaped truss foundation for single-axis trackers to the utility-scale marketplace as a cost-saving alternative to H-piles. Known commercially as EARTH TRUSS, this system relies on a pair of adjacent angled legs that form a truss with the ground.

When supporting single-axis trackers, truss foundations offer several advantages over conventional H-piles because they convert lateral loads into axial forces of tension and compression, rather than into bending moments. This enables the tracker to be supported with less steel and enables the below-ground components to be driven to shallower embedment depths than required for H-piles. Shallower embedment depths result in fewer refusals, thereby avoiding an expensive and time-consuming refusal mitigation process. Also, with the hollow, open-ended geometry of EARTH TRUSS components, it is possible to actuate a drilling tool through the screw anchor while it is driven into the ground, thereby speeding workflow relative to pre-drilling.

Despite their advantages, there are some climates where H-piles may outperform truss foundations. As the price of solar panels has dropped well below one dollar per watt, utility-scale solar arrays are being built in latitudes not previously cost effective for solar. Northern latitudes typically experience sustained sub-zero temperatures during the winter, which can be disruptive to foundations. The phenomena known as frost heave occurs where moisture in the portion of the soil from grade down to the frost line freezes, causing the ground to heave upwards. This can be disruptive to any foundation that does not extend below the frost line. This is especially true when the foundation components are oriented at an angle with respect to plumb. Sub-surface ice in contact with such components will tend to pull them upwards, applying a moment to the foundation. Where the depth of frost zone is substantial (i.e., multiple feet), such a moment may destroy or at least compromise the foundation. A similar phenomena may also occur in reactive clay soils that expand and contract due to seasonal changes in the moisture content of the clay that puts upward pressure on the truss foundation. To prevent this, various embodiments of the invention provide truss foundations that are optimized for use in climates that are subject to substantial frost heave during winter and/or to expansion and contraction due to changes in moisture content.

The following description is intended to convey a thorough understanding of the embodiments described by providing a number of specific embodiments and details involving A-frame foundations used to support single-axis solar trackers. It should be appreciated, however, that the present invention is not limited to these specific embodiments and details, which are exemplary only. It is further understood that one possessing ordinary skill in the art in light of known systems and methods, would appreciate the use of the invention for its intended purpose.

As mentioned in the background, single-axis trackers have traditionally been supported by monopiles, that is, rows of individual H-pile foundations. To compete with conventional H-piles, the Applicant of this disclosure introduced an A-frame-shaped truss foundation to the utility-scale solar marketplace known commercially as EARTH TRUSS. EARTH TRUSS consists of a pair of angled truss legs, extending below and above ground that are joined at their above ground ends with an adapter, truss cap or bearing adapter. This adapter, truss cap, or bearing adapter completes the A-frame-shaped structure and may provide a mounting surface to support a tracker component such as a bearing assembly or drive motor.

1 FIG.A 1 FIG.B 100 100 120 120 200 200 202 Turning to the Figures,shows EARTH TRUSS foundationin accordance with various embodiments of the invention whileshows the individual components used to construct it. Truss foundationis made of a pair of adjacent angled truss legs extending into underlying ground that are joined at the apex by truss cap or adapter. In this example, truss capis supporting single-axis tracker bearing assembly. Bearing assemblyis analogous to bearing assemblies used in the Dura Track HZ NX Series of single-axis trackers manufactured and sold by Array Technology, Inc. of Albuquerque, NM. In such a tracker, the torque tube, labeled “TT” in the figures, is seated within bearingand rotates about its own axis.

100 110 115 110 111 112 112 113 114 114 115 114 115 113 112 114 112 Each truss leg of truss foundationconsists of screw anchorand upper leg portion. Screw anchoris a section of elongated, hollow, galvanized steel tube (e.g., 1-2 meters) with external thread formas its lower end and driving couplerat the upper end. Driving coupleris welded or otherwise attached to the upper end and includes driving featuresthat are engage by the chuck of a rotary driver, and, connecting portionthat extends away from the driving features. Connecting portionis received in the open lower end of upper leg portion. Connecting portionhas a series of channels formed in it that provide recesses to deform upper leginto when a crimping tool is applied to the portion of the upper leg that overlaps with it. Driving featurescircumscribing coupleract as a stop to limit the extent to which connecting portionof couplerextends into the upper leg.

100 110 120 115 122 120 114 112 110 115 122 114 In various embodiments, trussis assembled with the assistance of a machine that is capable of driving the pair of adjacent screw anchorsat angles to one another on either side of an intended North-South tracker row. Then, truss capis held at the proper orientation, in some embodiments by a jig, holder or other device on the machine, to match the position and orientation of other truss caps in the same row. With the truss cap in place, upper leg portionsare sleeved over connecting portionsof truss capand over connecting portionof couplerat the head of screw anchor. Then, in various embodiments, a hydraulic crimping device is placed over the overlapping portions of upper legto deform it into the recesses formed in connecting portionsand. For a more thorough discussion of the machine see commonly assigned and co-pending U.S. patent application Ser. No. 17/095,616. For a discussion of assembling trusses with a hydraulic crimper, see commonly assigned and co-pending U.S. patent application Ser. No. 17/152,622. The disclosures applications nos. Ser. No. 17/095,616 and Ser. No. 17/152,622 are hereby incorporated by reference in their entirety.

2 2 FIGS.A andB 1 2 FIGS.and 130 220 120 130 132 115 120 130 134 220 220 226 224 220 222 224 Turning to, these figures show another truss capthat is particular designed to support bearing housing assembly. Like truss capin, truss capjoins the free ends of the pair of adjacent truss legs with a pair of connecting portionsthat are received in each upper leg portion. However, unlike truss cap, truss caphas a pair of support portionsdesigned to support tracker bearing housing assembly (BHA). BHAis a component of the NX Horizon single-axis tracker from NEXTracker, Inc. of Fremont, CA. NEXTracker's single-axis tracker is a top down or so-called mechanically balanced tracker where the torque tube hangs from a pin through their bearing housing assembly and swings through an arc that is bounded by the bearing housing assembly. A torque tube bracket is attached to the pin and to the torque tube. The drive motor in this tracker is offset so that its axis of rotation is aligned with the bearing pin rather than with the torque tube. The tube curves up on either side of the motor to pass through the slewing drive's gear assembly. According to NEXTracker, this configuration is mechanically balanced so that there are no overturning moments regardless of the angle of the panels. Rather than rotating about its own axis, the torque tube in the NEXTracker single-axis tracker hangs from a pin seated in bearingproximate to customof NEXTracker's cardioid-shaped BHA. Legsand cuspdefine a space that bounds the arc that torque tube TT is able to swing through as the tube is moved each day. The drive motor in such a tracker is offset so that the rotational axis of the tracker is the bearing pin rather than the torque tube. The various embodiments of the invention are applicable to either the ATI or NEXTracker style of single-axis trackers as well as various other trackers available in the marketplace.

3 FIG. As discussed in the background, in colder, Northern environments, truss foundations with angled truss legs that extend below ground may be more prone to failure than plumb-driven monopiles. To that end,, shows a truss foundation for use in regions with a relatively shallow frost zone. The arrows in this figure between the frost line and grade illustrate the problem of frost heave. Frost heave occurs when subsurface moisture and/or water in the soil in the frost zone freezes, causing an uplifting effect on the surrounding soil. So-called ice lenses form in this zone and can attach to foundation components, causing movement and even failure of the systems they support. Extending foundations below the frost line does not necessarily ensure that the supported structure will be prevented from frost heaving. Movement in the soil resulting from ice lens growth can be transmitted to foundation components if the ice freezes to them, even when a portion of the component extends below the frost zone. This phenomena can be particular acute where the columns or foundation components are oriented at non-plumb angles. In such cases, upward frost heave applies a non-axial adfreeze moment to the components that must be resisted.

3 FIG. 100 In the example of, truss foundationis anchored well below the frost line with very little of the truss legs passing through the frost zone. Because the upward force of frost heave is proportional to the amount of surface area of the foundation in affected zone, the adfreeze moment here will be relatively small and can be resisted with deep embedment depths and, if necessary, larger diameter anchors.

4 FIG. 3 FIG. 310 310 300 120 315 300 317 310 315 122 120 312 310 310 300 100 By contrast, in the example of, the frost zone is much larger. In this case, most of screw anchoris exposed in the frost zone. As a result, the adfreeze moment has the potential to be too large for the sub-frost zone portion of the foundation to resist. In order to compensate for this, truss legsof foundationhave been driven into the ground so as to be substantially plumb, and therefore aligned with the direction of heave. This does not eliminate adfreeze but does eliminate the adfreeze moment and therefore will not expose the screw anchors to non-axial forces. In order to utilize standard truss components, such as truss cap, upper leg sectionsof trusshave been modified to include elbow portionproximate to their lower end where they change from being angled toward the truss cap to being plumb to match the geometry of driven screw anchors. In various embodiments, upper legsare pre-bent to the appropriate angle to interface between connecting portionsof truss capand couplerat the top of plumb screw anchors. When frost heave and adfreeze occur here, the forces felt on screw anchorsare substantially axial. Because individual structural members are relatively good at resisting axial forces, truss foundationis much better able to remain intact in the face of frost heave and adfreeze than foundationin.

5 FIG. 6 6 FIGS.A-C 400 420 400 400 410 410 415 410 420 400 120 410 415 420 422 424 424 120 420 Turning now to, this figure shows truss foundationwhich is particularly well suited to frost heave applications in accordance with various embodiments of the invention.show various views of truss capused in truss foundation. Once again, foundationis built on a pair of adjacent, plumb-driven screw anchors. Though not shown, in various embodiments, screw anchorsare driven into the ground so that they extend well below the frost line. In this case, upper leg portionsare not pre-bent but instead substantially extend the axis of screw anchors. Truss capat the apex of trusshas a wider stance than truss capto accommodate the spacing between plumb oriented upper legs. In this example screw anchorsand upper leg portionsof each truss leg are substantially parallel to one another and separated by a distance of less than 1 meter (e.g., −2-feet). Truss caphas a handle shape with a pair of angled arms that terminate in downward projecting connecting portionsand meet centrally about elevated mounting platform. In various embodiments, a bearing assembly, tracker motor, or other tracker component is attached to mounting surface. Like truss cap, truss capmay be made from a single casting.

7 7 8 FIGS.A,B, and 7 FIG.A 7 FIG.B 8 FIG. 7 8 FIGS.B and 450 450 200 450 220 7 450 430 430 431 432 432 417 417 432 412 show another truss foundation for resisting frost heave forces according to various embodiments of the invention.shows completed truss foundation,shows foundationwith ATI bearing assemblyandshows foundationwith NEXTracker BHA. Starting withA, foundation, like other foundations shown and discussed herein, consists of a pair of two-piece plumb-oriented truss legs joined together with truss cap. Truss capaccording to this embodiment, has a 4-pronged star shape with two lower armsextending from the center at angles to one another and terminating in connecting portions. In various embodiments, these connecting portionsare received in upper leg sectionslike the connecting portions of other truss caps discussed herein. Where they meet the truss legs, they have coupler portions extending vertically that are received within the upper ends of each leg. See, for example,. In various embodiments, upper legs portionsare crimped where they overlap these connecting portionsas well as at the point of overlap with driving couplers.

430 434 200 430 200 7 8 FIGS.B and 7 FIG.B As shown, truss capalso has a pair of smaller upper arms that extend up and outward terminating in horizontal mounting platformsto support a bearing assembly or bearing housing assembly (BHA) such as that shown in, respectively. Starting with, this figure shows bearing assemblyof a conventional tracker such as the ATI DuraTrack HZ tracker discussed herein attached to truss cap. In such a tracker, torque tube TT is contained within bearing assembly, in some cases surrounded by a bearing insert, and is able to rotate about its own axis to change the angle of the attached solar panels.

450 430 417 432 412 417 Assembly of trussis accomplished in the same way as with other trusses discussed herein with a pair of adjacent screw anchors driven to be plumb on either side of an intended North-South oriented tracker row. In various embodiment, anchors are long enough so as to be driven to an embedment depth that enables the external thread for the anchor to penetrate below the frost line of the soil. Truss capis held in place using a jig or holder on the machine used to drive the screw anchors and upper legsare sleeved over connecting portionsand then down onto coupler. All over lapping areas of upper legare then crimped to secure the truss's orientation.

8 FIG. 430 220 222 434 shows truss capsupporting NEXTracker BHA. Legssit on support portionsCorp. of Fremont, CA. NEXTracker's single-axis tracker is a top down or so-called mechanically balanced tracker where the torque tube hangs from a pin through their bearing housing assembly and swings through an arc that is bounded by the bearing housing assembly. A torque tube bracket is attached to the pin and to the torque tube. The drive motor in this tracker is offset so that its axis of rotation is aligned with the bearing pin rather than with the torque tube. The tube curves up on either side of the motor to pass through the slewing drive's gear assembly. According to NEXTracker, this configuration is mechanically balanced so that there are no overturning moments regardless of the angle of the panels.

450 8 450 7 FIGS.A-B It should be appreciated that the foundationshown inandmay also support a tracker motor such as a slewing tracker motor that drivers a circular gear box in both top-down (mechanically balanced trackers) and conventional bottom up-trackers. Foundationmay also be used to support a center structure that turns the torque tube and transfers power across multiple rows, such as that used in the ATI tracker. It should be appreciated that any of the foundations disclosed herein may be useful for supporting tracker drive motors, drive assemblies, outer tracker rows or any other rows that may be subjected to more moments relative to the foundations supporting the inner tracker rows and/or bearings. These foundations may be used to support other structures as well.

9 FIG. 10 FIG. 11 FIG. 500 500 510 512 520 500 530 Turning now to, this figure shows a further truss foundationfor frost heave environments according to various exemplary embodiments. Foundation, as shown in the exemplary figure, consists of a pair of plumb driven screw anchorsthat are embedded below the active layer of the soil. The active layer may be the depth subject to frost heave, or alternatively, consist of expansive clay. Above ground, a pair of upper leg sectionsare joined to the screw anchors by elbow couplers. Truss foundationterminates in so-called bearing adapter. In the context of this disclosure, a bearing adapter combines the functionality of a truss adapter or truss cap to join the upper leg sections to form a unified truss foundation as well as providing an integrated tracker bearing to rotatably receive a section of the tracker torque tube. These components are shown in greater detail in the exploded view ofand in.

10 FIG. 12 FIG. 25 FIG. 11 511 511 510 522 521 521 522 523 524 512 524 524 523 523 522 525 520 512 525 522 521 521 522 520 524 512 533 530 In the exemplary illustration of, the upper driving details of screw anchorshave been omitted. In various embodiments, a ring of driving teeth or other features may be welded to the upper end of each anchor, such as, for example, driving ringshown in. Ringis show as symmetric, that is, each tooth is the same size, however, in other embodiments, the teeth on the ring may take on different shapes to enable the installation machine to know the orientation of the screw anchor relative to holes or other features on it as discussed in greater detail in the context of. Elbow couplerhas a lower endand upper and upper end. Each end,has a set of channels,respectively that provide voids for crimping into. When the truss is assembled, the lower ends of each upper leg portionare sleeved over the channels in connecting portionwhile channels of connecting portionof lower endare dropped into one of the driven screw anchors. Featureslimit the depth of penetration of couplerinto the screw anchor but also provide a registration point for a crimper so that the jaws of the crimper align with the channels regardless of the orientation of the upper leg to provide space for it to deform into regardless of the depth or position the upper leg section. It should be appreciated that although featuresare shown as rounded projections they may take on other geometries without departing from the spirit or scope of the various embodiments of the invention. Lower endand upper endare oriented at angles to another to enable plumb driven screw anchors to be joined to angled truss legs. An axis through the center of the upper endand lower endmay be separated, for example by approximately 20-degrees so that when coupleris inserted into a driven screw anchor, upper connecting portionmakes an angle of approximately 70-degrees with respect to horizontal. At the upper end, upper leg sectionsare sleeved over connecting portionsof bearing adapterso that crimp joints may be affected there as well where the upper leg section overlaps with the bearing adapter.

530 532 531 532 530 As shown in the figures, bearing adapterhas a bearing insertthat adapts the cross section of the torque tube to the bearing opening although other designs may be used to accommodate different trackers. As shown, a two-piece bodyclamps together to secure the bearing insert. Stops formed in bearing insertmay extend out of the opening of top half of bearingto prevent over rotation of the torque tube.

13 13 FIGS.A andB 550 510 600 512 520 560 600 560 510 show different views of a multi-legged motor truss foundationaccording to various embodiments of the invention. In the example shown, four screw anchorsare used to support the tracker drive motor. Four upper leg sectionsare attached to the screw anchors via elbow couplers. In this example, the truss legs are joined together via pan shaped truss adapter. Motor drive assemblysits on pan shaped truss adapterwith a convex base that enables its orientation to be adjusted relative to the adapter. In various embodiments, screw anchorsmay be driven in East-West and North-South orientations, that is, straddling the tracker row and along the direction of it to enable the legs to resist lateral loads as well as loads along the torque tube. Alternatively, the four screw anchors may be driven in an X pattern crossing the tracker row at 45-degree angles when viewed from overhead.

14 26 FIGS.- 14 FIG. 542 540 541 543 542 541 543 541 542 544 545 544 Remainingshow various elbow couplers usable with truss foundations having plumb driven below ground components according to the various embodiments of the invention. Starting with, this figure shows a flange type of coupler. In this example, screw anchorhas a flange-shaped headthat mates with flangeof coupler. In various embodiments, flangemay be used to drive the screw anchor into the ground, mating with reciprocal features of the chuck of a rotary driver on the anchor installation machine. Flangemay be fixed to flangeusing bolts, rivets or other suitable fasteners. This flange-on-flange fitment allows couplerto be rotated as needed so that it points at the intended location of the apex of the truss to enable the truss to be correctly assembled. Connecting portionis received in a lower end of one of the upper legs so that these two components may be crimped together where they overlap. Ringat the base of connecting portionlimits the depth of penetration, provides a pivot point to adjust the orientation of the upper leg, and also may provide a registration point to orient the crimper with respect to the channels formed in the connecting portion so that the blind crimp is successfully achieved every time regardless of the upper leg's position or orientation.

15 FIG. 550 550 552 556 553 550 554 555 555 542 544 554 556 550 shows another elbow coupleraccording to various exemplary embodiments of the invention. Couplerhas a reinforced insert sectionthat is inserted into the upper end of a driven screw anchor. Bolt holereceives a bolt that passes through both the screw anchor and the coupler. Ringsprevent the coupler from wobbling within the screw anchor. The upper portion of couplerhas a connecting portionwith ring. It should be appreciated that ringneed not have teeth because coupleris not used to drive the screw anchor but rather is added after the screw anchor is driven. As in other embodiments, connecting portionis received within the lower end of one of the upper leg portions and a crimp connection secures the upper leg to the coupler. Connecting portionis angled at the appropriate leg angle for the truss cap or truss adapter, for example, 20-degrees from the lower portion. Though not shown in the figure, the screw anchor must have a pair of matching holes formed in it to allow the bolt to pass through it and holesof coupler.

16 17 18 FIGS.,and 16 16 FIGS.A andB 21 FIG.C 16 FIG.B 560 560 561 622 621 562 560 563 563 563 564 565 564 560 In some cases, it may be advantageous for the elbow coupler to be made of two-piece construction. To that end, turning now to, these figures show additional two-piece elbow couplers according to various embodiments of the invention. Beginning with, these figures show two-piece elbow coupler. Couplerconsists of two halves that are joined together to fit over the head of a screw anchor. The screw anchor may have a pair of notches or holes cut in it like holesformed in anchorshown in. Halvesof couplerare fitted over the driven screw anchor so that holesalign with the holes formed in the screw anchor. Then, a bolt (not shown) or other fastener is passed through the holesand the anchor to secure the halves together over the upper end of the screw anchor. The machine driving the screw anchors will rotate when driving it so that the holes are clocked to the correct position so that when holesare aligned with the driven screw anchor, connecting portionswill point at the correct location in free space to enable the upper legs and truss cap or bearing adapter to be assembled. Ringacts as a stop and pivot point for the upper leg section when it is fitted over the connecting portions. When the upper leg section is crimped around the connecting portion, it will further unify the two-halves of coupler.shows the assembled coupler from the side (looking North or South) along the tracker row.

17 FIG.A 18 18 FIGS.A andB 570 570 573 572 571 573 574 573 571 570 580 573 584 584 570 580 570 and B show another two-piece elbow-coupler. Couperis made from two halvesthat each fit around a driving ring such as ringshown on screw anchorin the figure. When coupled together, halvesterminate in connecting portionsthat combine to form a single angled projection to receive the lower open end of one of the upper leg portions. A crimp joint over the upper leg section pinches the two halvestogether to form a unified coupler and secures the upper leg portion to the driven screw anchor.show a variant of coupleridentified in the figures as couplerthat includes overlapping lower flanges in each halfwith through holesthat enable bolts, rivets, or other fasteners to pass through to enable the two halves to be locked together before the upper leg portion is crimped to the connecting portions. In various embodiments, this may provide improved strength over couplerdue to the additional compressive strength provided by the bolts through each pair of overlapping flanges. Both couplerand couplerprovide the advantage that the rotation of the screw anchor does not need to be clocked so that the position of the bolt holes in the top of the anchor will ensure that the elbow coupler is pointing at the correct point in free space to enable the truss foundation to be assembled. With other elbow couplers shown and discussed herein with holes cut or punched in them, the screw anchor must be rotated within a few degrees of the correct position for the reciprocal features of the anchor to align with the coupler at the correct orientation.

19 FIG.A 590 590 592 593 594 and B show still another variant of an elbow couplerfor truss foundations according to various other exemplary embodiments of the invention. Couplerhas a hood portionthat includes openingsspaced around its underside to enable it to receive the teeth of the driving ring when slide down over it. Once placed over the driving ring, the coupler is rotated a partial turn to lock it into place on the screw anchor. Then, upper leg portion is sleeved down over connecting portionso that it may be crimped into place thereby locking the components together.

20 FIG. 600 600 602 605 602 612 610 600 610 605 612 604 603 600 604 605 shows another elbow coupleraccording to various embodiments of the invention. Coupleris a one-piece coupler with a main housing portionthat is open at the lower end. As shown, projectionis formed on the inside wall of housing. That projection is a received in a corresponding slotformed in the head of screw anchor. Coupleris fitted over the upper end of screw anchorand twisted allowing it to slide down onto the screw anchor as projectionmoves down along slot. At the upper end, connecting portionincludes several crimp channels and a ringto limit the extent of penetration when an upper leg portion is sleeved down onto the coupler. A coupler such as couplerwill require the position of the slot to be known to the installation machine when driving it into the ground so that when the coupler is fitted to the head of the screw anchor, and fully twisted down onto it connecting portionwill point at the correct location in free space to assemble the truss foundation. It should be appreciated that although a single projectionis shown in the figure, in various embodiments, two or more projections may be used requiring two or more channels formed in the upper end of the screw anchor.

21 21 FIGS.A andB 21 FIG.C 23 23 FIGS.A andB 24 24 FIGS.A andB 23 FIGS.A 620 620 623 621 624 623 622 626 628 620 647 646 643 641 644 650 650 653 652 653 658 651 655 657 645 647 show yet another elbow couplerfor truss foundations according to various exemplary embodiments of the invention;shows a screw anchor usable with such a coupler. Coupleris similar to other couplers shown and described herein. It has a double-walled housingthat fits over the upper end of screw anchorbut also inside of it via inner portion. Boltpasses through holesformed in the upper end of the screw anchor and is secured with a nut. Upper connecting portionincludes a plurality of crimp channels and stop ring.show a variant of couplerthat includes impact surfacebelow connecting portionfor beating on it with a blunt tool such as a hammer to force housingdown onto the upper end of screw anchor. Boltpasses through both pieces to lock the coupler to the screw anchor at the desired orientation.show coupleraccording to a further variant. Coupleincludes leg brace mountson opposing sides of the surface of housingfor supporting a leg brace. At certain foundation locations where the forces are greater relative to other locations (e.g., trusses along the perimeter of the array, motor trusses, etc.), it may be necessary to include an additional leg brace connecting the coupler on the top of one screw anchor to the coupler on the adjacent screw anchor supporting the same truss. Leg brace mountsshown in the figures have a semi-circular geometry with teeth to hold a leg brace interconnecting one coupler to the coupler on the adjacent screw anchor supporting the same truss. As pictured, U-boltpasses though the housing and the upper legto secure the coupler to the screw anchor as well as the leg brace to the coupler. Elementsandas shown are the same as elementsandofand B.

25 26 FIGS.and 25 FIG. 663 663 663 666 510 667 666 661 510 510 511 664 665 664 664 668 Turning now to, these figures show another one-piece elbow coupleraccording to various exemplary embodiments of the invention. Couplerhas a helmet shaped housingwith a pair of bolt holesformed in opposing flanges. When mated to a screw anchor, such as anchorshown in, boltpasses through holesin the coupler as well as through holesin the upper end of screw anchor. As shown, screw anchorhas an asymmetric driving ringthat is used to drive the anchor into the ground. Connecting portionhas crimping rings formed in and projectionsspaced around the base of connecting portionact as a depth limiter as well as providing a feature to registered the crimper so that the jaws align with the channels formed in connecting portionso that when blind crimp joints such as jointsare made, the upper leg section deforms into the channels regardless of the angular orientation of the upper leg with respect to the connecting portion.

630 631 630 631 633 634 635 636 22 22 FIGS.A andB Unlike other embodiments shown and discussed herein, elbow couplershown inis fixedly attached to the head of screw anchor, that is, coupleris attached to the head of anchorwhen it is driven into the ground. The drilling tool on the installation machine driving the screw anchor passes through openingat the top. This will require stopping the rotation of the screw anchor so that upper projectionwith connecting portionis pointing at the correct point in free space to enable the truss to be assembled. Stop ringagain acts as depth limiter and provides a pivot point to adjust the angle of the upper leg when joining the leg to the coupler.

27 FIG. 670 is a flow chart detailing steps of an exemplary method of assembling a truss foundation according to various embodiments of the invention. The exemplary method begins in stepwhere a pair of adjacent screw anchors are embedded on either side of an intended tracker row. In various embodiments, this is done with a proprietary automated drilling and driving machine manufactured and sold by the applicant, OJJO, INC. of San Rafael, CA under the commercial name “TRUSS DRIVER.” As discussed herein, the screw anchors are driven at a plumb orientation to extend below the active layer of the soil. When using elbow couplers that require a precise orientation of the screw anchor, the automated machine may keep track of the number of rotations required to embed the anchor so that the head of the driven anchor will present attachment features for the elbow coupler so that the coupler points at the correct location in free space to assemble the truss.

675 680 685 690 At step, if not already fixed to the screw anchor, an elbow coupler is attached to the top of each driven screw anchor. In various embodiments, this may be done by passing one or more bolts through each elbow coupler and screw anchor and securing them with a nut. Then, at step, the truss cap, bearing adapter or other apex component is held above the pair of driven screw anchors at the precise orientation. In various embodiments, the automated truss drive machine will self-orient a jig on the mast of the machine so that the apex truss component is held at the correct position above the pair of driven screw anchors. Next, at stepan operator places upper sections by sliding them up over connecting portions of the truss cap, bearing adapter, etc., and then down onto the connecting portion of the elbow coupler. Then, at stepa hydraulic crimping machine is then used to crimp the portions of each upper leg that overlap with the truss cap and the elbow coupler to unify the truss foundation at the correct orientation.

The embodiments of the present inventions are not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the embodiments of the present invention, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such modifications are intended to fall within the scope of the following appended claims. Further, although some of the embodiments of the present invention have been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the embodiments of the present inventions can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breath and spirit of the embodiments of the present inventions as disclosed herein.